Abstract: A novel contrast sensitivity test utilizing an adaptive contrast threshold algorithm is proposed. The contrast sensitivity test is embodied as a two-alternative forced choice examination using grating stimuli of randomly interleaved spatial frequencies. The stimulus's orientation is either tilted to the left or right of vertical. During an examination, a succession of grating stimuli is presented to the subject, and the subject asked to indicate the orientation of each stimulus. The contrast level for the next stimulus is varied depending on the subject's response to the previous one using an adaptive weighted up-down algorithm. For each correct response, the contrast level is reduced, whereas for each incorrect response the contrast level is increased. Importantly, the amount by which the contrast level is lowered is different from the amount by which it is raised, and as the examination progresses, the amount changes.

Abstract: A method and apparatus are disclosed for improving channel equalization and enhancing timing recovery during level learning in a data communication system. The disclosed equalizer training process separately updates the feed forward filter (FFF) and the level adapter, to gain additional improvements in the training of the feed forward filter (FFF). The multi-step equalizer training process initially trains the feed forward filter (FFF) using a two-level signal EQTR(n) having an ideal value to help converge the feed forward filter (FFF) to a certain level. Once the feed forward filter (FFF) reaches a certain level of convergence, the training circuitry is reconfigured to evaluate and update the actual level of the signal EQTR(n). The determined weighting factors are applied to a low pass filter and the actual level of the signal EQTR(n), B(n), is calculated. The actual level of the signal EQTR(n), B(n), is then applied to the level adapter.

Abstract: The present invention provides a method for establishing fixation during computerized visual field perimetry, requiring the subject to fixate on a stationary target for a brief instance as he/she moves a secondary target towards the stationary target. In a preferred embodiment, the subject interactively moves the secondary target in the shape of crosshairs toward the stationary fixation target displayed on a monitor using the operations of a computer mouse. The stationary fixation target has preferably the shape of a small red circle in order to make it readily identifiable by the subject. The computer mouse pointer when contacted attaches itself to the secondary target. The subject then moves his head so that the fixation target is directly in front of him/her, and, while staring at the fixation target, moves the secondary target towards the stationary fixation target.

Abstract: A technique for evaluating the topography of a cornea is disclosed, which utilizes a virtual image/object of a keratoscope pattern. The disclosed topography system includes a structured light source to create the keratoscope pattern or another diagnostic pattern, an optical assembly to focus the created pattern upon or behind the cornea, and for capturing the image reflected off the patient's eye and directing the reflected image toward an imaging system for processing. Light emitted by the light source is preferably not in the visible range, to minimize discomfort to the patient. Since the topography is evaluated with a projected virtual image, there is no nose or brow shadow, thereby allowing better corneal coverage. The optical system includes an aperture stop which is preferably conjugate with a point behind the corneal surface approximating the center of a normal cornea.

Abstract: The present invention is addressed to solving the problem of AR coating lenses having at least one or more. textured translucent regions, without altering the effectiveness of the translucent regions to reduce glare. A part of the uniqueness of the present invention is that the AR coating is applied on the surface that opposes the translucent region. As such, part of the invention is the discovery that AR coating the lens on the surface opposing the translucent regions does not limit its ability to block glare inasmuch as the coating does not alter the surface contour of the translucent region.

Abstract: A broad band optical amplifier includes at least one free space wavelength demultiplexer/multiplexer and optical gain means. The free space demultiplexer/multiplexer receives a multiplexed signal and spatially separates it into a plurality of spectral components each having a unique peak wavelength. The optical gain means has a plurality of wavelength-selective gain regions that are capable of imparting gain to (i.e., amplifying) an optical signal over a particular narrow range of wavelengths. The operational range (i.e., the particular narrow range of wavelengths) of each gain region is unique. The spatially-separated spectral components are individually delivered to specific gain regions by the demultiplexer/multiplexer as a function of the peak wavelength of the spectral component and the operative range of the gain region.

Abstract: A method for creating signal unidirectionality in electronic circuits is disclosed. This invention describes a method for achieving unidirectionality in an electronic circuit with an input side having a signal source and an output side with a load comprising detecting the current passing through the load on the output side, bypassing a portion of the current passing through the load on the output side, and feeding the bypassed portion of the current on the output side to the input side to achieve unidirectionality. Specifically, unidirectionality in an electronic circuit is accomplished by applying feedback such that the impedance looking into the input of the amplifier is increased. These methods are particularly applicable to negative resistance amplifier circuits.

Abstract: The present invention is directed to a novel wavelength division multiplexed (WDM) lightwave communication system having allocated wide bands of wavelengths within which the respective optical pump light employed to amplify the optical signals must stay. As the temperature of the pump laser varies, its lasing wavelength is allowed to wander anywhere within its allocated wavelength band. Preferably, the pump lasers are wavelength stabilized within its respective allocated wavelength band by means of a fiber Bragg grating having an appropriately wide spectral width. Extending the lasing wavelength range of the pump laser advantageously, in turn, may be used to extend the temperature range over which the pump laser can be operated or locked.

Abstract: The present invention discloses a method for eliminating, or at least minimizing, the locking range variability of laser modules which employ external grating, such as fiber bragg gratings. It has been observed that the coupling efficiency between the laser and its output fiber is a highly variable property of the laser module, causing variations in the laser module's locking range. The laser module's locking range, however, can be readily reset to or near its nominal value by measuring the laser module's coupling efficiency, and then judiciously choosing a grating having a peak reflectivity which compensates for variations in the coupling efficiency by maintaining constant the effective reflectivity Reff of the fiber/grating combination.

Abstract: A hybrid integrated optical transmitter comprising a wavelength selectable laser (WSL) source coupled to an optical amplifier/modulator has been realized. Disposed between the optical combiner and the optical amplifier/modulator is an “optical isolator.” The optical isolator includes at least a Faraday rotator and, either solely or in combination with a single polarizer and/or half-wave plate is used to selectively rotate and pass polarized light egressing from the wavelength selectable laser source. Optical isolation is achieved by the egressing radiation from and back reflections incident on the laser source being at two mutually exclusive orthogonal polarization states or by the reflections being totally extinguished. Advantageously, the laser source is unresponsive to orthogonally polarized light, and hence any unwanted back reflections do not substantially affect the operating characteristics of the laser(s).

Abstract: The present invention is directed to a method for adjusting the operating temperature range of a laser module such that it substantially covers or is coextensive with the span in temperatures for the desired application. In accordance with the principles of the invention, it has been found that the laser module's operating temperature range can be readily adjusted by judiciously increasing its thermal resistance so as to elevate, and thereby offset the laser's temperature from its ambient or surrounding temperature. As such, by judiciously impeding the laser module's heat flow, the laser module's operating locking temperature range can be made to be cover the span in temperatures for the desired application. Preferably, washers of a known thermal resistance are employed to increase the laser module's thermal resistance to accordingly impede heat flow from the laser to its surroundings, and thereby offset the laser's temperature.

Abstract: A limitation of using two-dimensional images, such as videos or photographs, to represent portions of a three-dimensional world occurs when the user moves within the world and views the world from a location different than from the original context of the two-dimensional image, i.e., from a location different than the image's ideal viewing point (IVP). View changes result in the image not aligning well with the surrounding objects of the three-dimensional world. This limitation is overcome by distorting the two-dimensional image so as to adjust the image's vanishing point(s) in accordance with the movement of the user using a pyramidic panel structure. In this manner, as the user moves away from the ideal viewing point, the distortions act to limit the discontinuities between the two-dimensional image and its surroundings.

Abstract: A novel psychophysical visual test based on the visual response of the eye to alternating chromatic complementary colors or achromatic grays of varying saturation, luminance and/or contrast is proposed for the early detection of glaucoma, and other diseases. In one embodiment, although the luminance level remains constant, the visual stimulus alternates between two complementary or counter phase colors, preferably against a gray background at about 40 times a sec, for example, between blue and yellow. When the colors are alternated in this manner, the visual stimulus appears white or gray to an observer, instead of either blue or yellow. As the saturation is reduced, however, the alternating colors appear grayer, and then eventually cannot be perceived. Persons suffering from glaucoma and other diseases, however, find it more difficult than normal people to distinguish the visual stimulus as the saturation and/or luminance is reduced.

Abstract: A limitation of using two-dimensional images, such as videos or photographs, to represent portions of a three-dimensional world occurs when the user moves within the world and views the world from a location different than from the original context of the two-dimensional image, i.e., from a location different than the image's ideal viewing point (IVP). View changes result in the image not aligning well with the surrounding objects of the three-dimensional world. This limitation is overcome by distorting the two-dimensional image so as to adjust the image's vanishing point(s) in accordance with the movement of the user. In this manner, as the user moves away from the ideal viewing point, the distortions act to limit the discontinuities between the two-dimensional image and its surroundings.

Abstract: The present invention provides a bi-directional vehicle communication network which has the ability for record management and collection, including updating registration, insurance, inspection and/or maintenance records, as well as for collecting for the transaction fee or cost thereof. Additionally, the present vehicle communication network readily affords the ability of ticketing drivers for traffic violations. Importantly, vehicles are equipped with an electronic tag containing records associated therewith. In response to radio frequency signals from a portable interrogator, vehicular records may be selectively retrieved from the electronic tag. Updated records are then transmitted to the electronic tag for storage. Similarly, those updated records may be also transmitted to a centralized control center for archival purposes, as well as for effecting collection.

Abstract: The present invention is a method for compensating for stress induced in optical components used to couple light egressing from the housing of optical modules employing, for example, a distributed optical isolator. It has been discovered that this induced stress may be counteracted by transmitting a balancing or compensating force so as to produce a counter-stress in the optical component. Preferably, the method uses pairs of circumferential laser welds judiciously formed a distance form the holder housing the optical component so as s to control the magnitude and direction of the applied compensating force and, hence, the counter-stress transmitted to the optical component. During welding, the effects of the induced stress are monitored and based upon any changes therein, pairs of laser welds are formed around the circumferential surface of the housing of the optical component until the induced stress is substantially reduced or eliminated.

Abstract: An apparatus for assessing the visual field of a patient is disclosed which utilizes a virtual image of a visual stimulus. The disclosed apparatus includes a light pattern generator which generates a visual stimulus, such as a moving fixation target, and an optical assembly which produces a virtual image of the visual stimulus projected a distance in front of the patient's eye. During measurement of the patient's visual field, the patient observes the virtual image of the visual stimulus. A centration illumination source, such as an infrared laser, also illuminates the patient's pupil with an infrared beam, which is then scattered off the patient's iris. In operation, the apparatus monitors the patient's fixation on the visual stimulus by tracking the movement of the patient's pupil using the scattered infrared image. When the center of the pupil image moves beyond a predefined threshold, a lost of fixation is indicated, from which the patient's visual field can be assessed.

Abstract: The present invention is addressed to a method for fabricating lenses having at least one or more translucent regions used to reduce glare and/or increase visual acuity. To overcome the limitations of the prior art, an injection mold die having a selective portion thereof textured with a pattern or so-called "texture," which is replicated on the lens during injection molding, is employed to form a region of desired translucency on the finished lens. Various methods may be employed to fabricate the texture or pattern on the desired surface portion of the mold die, including mechanical engraving, chemical etching, and electrical-erosion machining (EDM and ECM). Typically, the texture or pattern includes multiple grained features of a quasi-repeating geometrical pattern distributed on the selected portion of the mold die.

Abstract: The diagnostic system of the present invention monitors and accumulates the thermal signatures or characteristics during at least one operational mode of the cooking appliance. These thermal signatures or characteristics are collected--through the same temperature sensor used to regulate the temperature of the cooking appliance--and then stored in, for example, a look-up table. Advantageously, this may be accomplished without the need of special sensors or interface boards. The thermal signatures or characteristics may include first order or higher order temperature gradients, as well as temperature profiles. The stored thermal signatures provide a baseline from which the diagnostic system can detect and identify whether the cooking appliance is working under normal operating conditions. In an alternative embodiment, the diagnostic system monitors and accumulates the cooking profiles for either a single food product or a plurality of food products.

Abstract: The present invention is directed to a lifting and positioning system for use by a single person in installing onto or removing from an elevated position a microcell module, all without the aid of major powered machinery. In addition to the use of a portable hoist, a bracket for permanently mounting the microcell module to a desired surface at the installation site, and a lifting bracket that detachably mounts to the module, the lifting and positioning system of the present invention uses structural features of the microcell module itself to simplify installation and removal. In this latter manner, only a relatively small number of parts need to be carried to the installation site, and can be done so safely and without undue bodily strain.